Code securitization and code validation/verification for digital computer systems is becoming increasingly important due to numerous avenues available for malicious attack or inadvertent error in complex data processing systems. Examples of malicious attack include those based on infection by software viruses, worms, and Trojan horses as well as those based on loophole exploitations. Attacks can also come directly from unscrupulous but authorized users of a computer system. Attacks may attempt to modify executable program code or to modify critical informational data items or inject new unauthorized program code or to gain access to key pieces of informational data that are preferably kept proprietary. Inadvertent mistakes during code development may produce similar faults and failures. Measures for preventing such faults and failures are accordingly becoming increasingly important.